A5100392141- Optical measurement and interference techniques
- Surface Roughness and Optical Measurements
- Advanced Measurement and Metrology Techniques
- Optical Polarization and Ellipsometry
- Digital Holography and Microscopy
- Optical Systems and Laser Technology
- Adaptive optics and wavefront sensing
- Optical Coherence Tomography Applications
- 3D Surveying and Cultural Heritage
- Optical Coatings and Gratings
- Advanced Surface Polishing Techniques
- Remote Sensing and LiDAR Applications
- Hydraulic and Pneumatic Systems
- Near-Field Optical Microscopy
- Industrial Technology and Control Systems
- Structural Health Monitoring Techniques
- Advanced optical system design
- Advanced Fiber Optic Sensors
Fudan University
2019-2025
Nanjing University of Aeronautics and Astronautics
2024
Chinese Academy of Sciences
2017
Changchun Institute of Optics, Fine Mechanics and Physics
2017
Heriot-Watt University
2011-2014
University of Electro-Communications
2004-2006
Research Institute of Highway
1992
Accurate in situ measurement of complex optical surfaces is desired for precision manufacturing, and deflectometry a promising measuring method. However, deflectometry's accuracy depends heavily on the geometric calibration's reliability. Existing calibration methods suffer from limitations low efficiency, complicated operations, expensive equipment. Therefore, self-calibration method proposed monoscopic order to determine camera screen positions. A flat mirror without markers, rather than...
Infrared deflectometry is an efficient and accurate measuring method for curved surfaces fabricated via grinding or finish milling. The emitting properties geometrical configurations of the infrared light source a core component governing measurement performance. In this paper, slit designed based on cavity structure polyimide heating film. This design ensures good stability uniformity whilst effectively reducing background noise. Additionally, can be applied as calibration board calibrating...
Extra detections of feature points conducted by a third-party instrument are indispensable in the monoscopic deflectometry to specify surface position, but measuring capability can be limited because most freeform surfaces do not contain any distinguishable and detectable points. In this Letter, behaviors position error form measured discriminated reverse ray-tracing. A novel iterative optimization strategy is developed workpiece for situ deflectometric measurement so that extra avoided. It...
To provide a theoretical background for the superiority of signal-domain phase-only correlation (SDPOC) technique proposed here microdisplacement measurement, we study first- and second-order statistical properties complex amplitude an analytic signal white-light speckle pattern, under assumption Gaussian random process, give formula autocorrelation function pseudophase associated with signal. Based on these results, show mathematically that SDPOC has performance advantage over conventional...
In the past 10 years, adaptive wavefront interferometry (AWI) has been employed for measuring freeform surface profiles. However, existing AWI techniques relying on stepwise and model-free stochastic optimizations have resulted in inefficient tests. To address these issues, deterministic (DAWI) is firstly introduced this paper based backpropagation (BP), which employs a loss function to simultaneously reconstruct sparsify initial incomplete interferometric fringes until they are nulled. Each...
Phase-induced amplitude apodization (PIAA) is a promising technique in high contrast coronagraphs due to the characteristics of efficiency and small inner working angle. In this letter, we present new method for calculating diffraction effects PIAA based on boundary wave theory. We propose numerical propagator an azimuth integral form, then delve into its analytical using stationary phase approximation. This has straightforward physical meaning obvious advantage efficiency, compared with...
The measurement of aspheric surfaces is very difficult and challenging. An optical system with a single coated lens proposed for measuring large-aperture convex/concave surfaces. In this system, the first surface compensator used as an auto-collimation surface, which can realize high-precision null compensation. Based on third-order aberration theory, initial design parameters are obtained by analytical calculation, then optimized numerically. oblate spheroid equivalent aperture 426 mm taken...
In one-dimensional (1D) signal analysis, the complex analytic built from a real-valued and its Hilbert transform is an important tool providing mathematical foundation for 1D statistical analysis. For natural extension beyond signal, Riesz has been applied to high-dimensional processing as generalized construct vector representation therefore, enlarge traditional concept. this paper, we introduce correlations new tools calculus speckle Based on of pattern, present associated correlation...
Non-contact optical measurement is a potential approach to on-orbit vibration for flexible appendages, providing dynamic information spacecraft control system. Binocular photogrammetry system practical configuration achieve this measurement. In paper, optimization and strategy parameters of are raised. Measurement matrix specially defined obtain the objective function optimization. Successive linear programming algorithm used iteration. Transient responses appendages calculated by finite...
The Beta distribution can effectively describe the non-Gaussian statistical characteristics of electromagnetic scattering. Conventional random fields always implicitly assume that number steps is infinite, but in practice, it finite. In this paper, we investigate properties distributed light field, and analyze new theory by combining resulting probability density function Stokes parameters.
Interference, where the superposition of two or more waves resulting in a new wave pattern, has been considered as one most important and fundamental physical phenomenon. In optics, statistical properties light play an role determining outcome optical experiments cross correlation between fluctuating fields at different space time points, known coherence functions, is quantity great interest. Due to fact that equations govern propagation coherence, it can be envisaged interference phenomena...
Some second-order statistics for partially developed speckle have been investigated and analytical expressions the cross-correlation function derived. Experiment results are provided to demonstrate validity of proposed theorem.
Under the assumption of Gaussian random process, we discuss first and second order statistical properties complex amplitude analytic signal white-light speckle pattern. We derive autocorrelation function pseudo phase. Based on these results, show mathematically that proposed domain phase-only correlation (SD-POC) has advantage over conventional intensity-based techniques in its performance micro-displacement measurement. also present experimental results support theory.
As an alternative to the intensity correlation technique used in conventional speckle metrology, we propose a new of displacement measurement based on spatial signal-domain phase-only that makes use pseudo phase complex analytic signal generated from Hilbert-filtered pattern. Experimental results are presented demonstrate validity and advantage proposed over technique.
Optical metrology provides direct feedback for AR/VR/MR design verification and manufacturability evaluation by imitating the human eye's optical properties of resolution, color sensitivity uniformity over large FOVs, self-adaption to focus location, brightness contrast. This paper defines a generic, standardized platform efficiently integrate various instruments into platform's global coordinate system utilizing specially designed active-optical calibration target precisely map entrance...
The aspheric surfaces can be tested with using the interference type computer--generated holograms (CGH). However, system errors which exist in optical arrangement affect measurement result. For this reason, paper proposes a new method CGH to compensate errors, Zernike polynomial analysis and calculation are applied. is verified by experiment.